Field of the Invention
The present invention relates to an imaging apparatus having an imaging element in which a plurality of light receiving elements is arranged with respect to one micro lens and a method for controlling the same.
Description of the Related Art
Conventionally, stereo cameras that are capable of photographing images for three-dimensional display or stereoscopic display have been proposed. Japanese Patent Laid-Open No. 01-202985 discloses an apparatus that acquires a stereo image including a left-eye image and a right-eye image using two optical units and two imaging elements. Japanese Patent Laid-Open No. 58-24105 discloses a method for acquiring left-eye image data and right-eye image data using a single optical unit. Also, a solid-state imaging element having pixels each having a micro lens and a plurality of photodiodes each of which is separated is known. By taking advantage of the fact that each photodiode receives light on a different pupil plane, stereo image data can be acquired.
In addition, digital cameras that display image data captured from an imaging element in real-time (live-view display) such that a user can capture a still picture image while confirming the composition thereof have become popular. For autofocus (hereinafter also referred to as “AF”) control during live-view shooting, Japanese Patent Laid-Open No. 2008-028747 discloses a method for continuously performing AF control during live-view shooting while automatically tracking an object designated by a user.
When an imaging apparatus performs live-view shooting while acquiring a stereo image and automatically tracks an object at the same time, the following circumstance may occur. FIG. 10 is a schematic diagram illustrating parallax-free left-eye and right-eye images on the top side and parallax left-eye and right-eye images on the bottom side, where an object is represented by a triangle. When there is no parallax between the two, the position of an object image is matched between a left-eye image and a right-eye image. However, when there is a parallax between the two, the position of an object image is not matched between a left-eye image and a right-eye image. In particular, when an object moves along a direction of the optical axis of a camera, the each position of the object image for a left-eye image and a right-eye image move in opposite directions as illustrated by the arrows. When an AF operation is continuously performed while tracking an object, AF control may be performed at a position which is displaced from the actual position of the object.